Augmented optical and electrical properties of PMMA-ZnS nanocomposites as emissive layer for OLED applications

We report the laboratory synthesis of Poly methyl methacrylate (PMMA)-Zinc sulfide (ZnS) nanocomposite via free radical polymerization method and its structural, optical, electrical, and dielectric properties for various concentration of ZnS nanoparticles. The formation of PMMA, ZnS and PMMA-ZnS nanocomposites was examined by X-ray diffraction technique, Fourier transforms infrared spectroscopy and FT-Raman spectrometer. Morphological structure of PMMA-ZnS nanocomposites showed the combination of pebbled and nanosphere like structure. The in-depth topological images were examined by transmission electron microscopy which indicated that the particles were fairly in good contact. The optimized and reduced band gap was calculated similar to 3.30 eV. The photoluminescence spectra showed blue, green and yellow band with increased rate of e(-)-h(+) recombination. The decay time of the PMMA-ZnS (5.0%) nanocomposite was similar to 4.8413 ns, and the color purity was calculated similar to 34.08%. The current density increased 249% which indicated the enhancement in conductivity. The dielectric properties of the PMMA-ZnS (5.0%) showed high dielectric constant with a very low dielectric loss. The reduction in optical band gap, high dielectric constant, and increased conductivity with increased in recombination rate confirmed that the as-prepared PMMA-ZnS nanocomposite can be used as an emissive layer in OLED devices.